No disrespect but shoudln't you actually know this question you are posing to us? I mean you are offering seo training to your customers? And part of proper seo is "seo copywriting"
But I will try to explain the question so that it may benefit you.
Anyone can rank a keyword with few simple rules that Google suggests in their webmasters guidelines here >>> http://support.google.com/webmasters/bin/answer.py?hl=en&answer=35769
Second of all, you can read and learn some programming languages, like C, php, functional programming etc (well at least understand what it is) then you can learn more about how Google works by reading and watching and testing, more can be read here >>> http://code.google.com/edu/submissions/mapreduce-minilecture/listing.html
But this is just the beginning to take shape and form to answer your question, meaning, you can then watch Matt Cutts videos and try to understand some points about seo (since he slips somethings which he shouldn't)
then test, re test and then test some more. Anyhow, to cut the story short, once you get bit of an idea about all this, then, and only then, can you talk to Googlebot and your customers at the same time, because that is the question put forth, how can I create content for seo and also my potential customers.
You may at this stage think what in the world is the person talking about? right? but we need to know, Google does use some artificial intelligence within their technology, start here type "breadth first search" into Google since all these factors must be taken into account when creating content for seo purposes. Because seo is just that, communication, both to Google and also your human visitors, thus, always have the interests of your human readers, first.
I hope this reply starts you on a journey to answer your very complex question